(a) Technical Field
The present invention relates to a short-circuit detecting apparatus and method of a heating system for a high voltage battery. More particularly, the present invention relates to an apparatus and method that detects a short-circuit of a heating system that increases the temperature of a high voltage battery used as a main power source in electric vehicles.
(b) Background Art
Generally, a high voltage battery used in electric vehicles and hybrid vehicles shows different output characteristics based on the temperature of the high voltage battery. As the temperature of the high voltage battery decreases, the available output thereof is reduced. When driving a vehicle which has been parked for a substantially long time in cold weather such as a substantially low temperature environment of about −10° C. or less, the available output of the high voltage battery decreases significantly compared to a required output of a vehicle. Accordingly, clattering of a vehicle may give an uncomfortable feeling to a driver, and may acceleration from being capable of occurring.
Particularly, an electric vehicle using only a high voltage battery as a main power source is substantially sensitive to the temperature of the battery as compared to a hybrid vehicle. Accordingly, to prevent the output reduction of the high voltage battery, the output of the high voltage battery must fall within a predetermined range by heating the high voltage battery.
FIG. 1 is an exemplary view illustrating a heating system for a high voltage battery which is currently being applied to an electric vehicle. The heating system 1 includes 8 heaters 2 which are connected in series. The heating system 1 heats the battery by applying a current to the heater 2 including a Positive Temperature Coefficient (PTC) thermistor using the voltage of the high voltage battery. Thus, the heating system operates about 30 minutes earlier than the starting time desired by a user, allowing the high voltage battery to be heated from about −20° C. to −10° C. for 30 minutes.
Since the heating system uses a high voltage, it is important to detect a cut-off, short-circuit, and fusion from a viewpoint of fail safe. As a typical method that detects a short-circuit of a heater, there are various methods such as a current sensor, a temperature sensor, and a voltage sensing of respective heaters. The method that detects the short-circuit of the heater using the temperature sensor includes two temperature sensors attached to a location where the heater in the heating system may be short-circuited, and determines the short-circuit by comparing the temperature of a short-circuited heater with that of a normal heater (e.g., a heat that is not short-circuited).
However, the temperature sensor that detects a cut-off, requires about eight temperature sensors to increase accuracy of the detection, thus increasing a manufacturing cost.
The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.